tough to say, he is estimated to be about 9-10 years old and they can grow up to 24 inches in the wild..... but in captivity i would expect tops another 4 inches or so. and that will probably come over some long period of time. the fish has a lifespan of up to 40-45 years. I know within a few years i NEED my bigger tank. If he gets too much bigger he wont fit in my 180 and I dont want a small living arrangment to lessen his lifespan either.